class_docstr: Calculate confusion matrix metrics for each subgroup
  
  Parameters
  -----------
  sub_confusion_matrix : SubgroupConfusionMatrix
      Object with calculated confusion matrix values for each subgroup
  
  Attributes
  -----------
  subgroup_confusion_matrix_metrics : dict
      Dictionary with confusion matrix metrics for each subgroup
code: def __str__(self):
      return (
          f"Object _SubgroupConfusionMatrixMetrics was converted` to data frame, top rows: \n"
          f"{self.to_vertical_DataFrame().head().to_string()}"
      )
  
imports: from copy import deepcopy
  import numpy
  import pandas
  from .None import checks
  from ...None import _global_checks
  from ..._explainer import helper
  from ...model_explanations._model_performance import utils
label_desc: Use image node_id 4 for calling the SubgroupConfusionMatrixMetrics obj's underlying member method code with example usage: obj.__str__() and returns: str, self